Spintronic phase transition of graphene/BN/graphene van de Waals heterostructures

Abstract

Based on a single-orbital tight-binding (TB) Hubbard model under mean-field approximation, we study band structure and half-metallicity of zigzag graphene/boron nitride/graphene (Z-G/BN/G) trilayer nanoribbon systems. Under different Coulomb repulsion and local potentials, the system will exhibit metallic, half-metallic and semiconductor phases, and the corresponding phase transition regions are also different. For the three stacking sequences, a large local potential on the top layer can destroy its half-metallicity. For AAA and ABA stacking, half-metallicity can occur in top or bottom layer, whereas half-metallicity occurs in bottom layer for ABC stacking. This indicates that the stacking sequence can be a new degree of freedom to tune the half-metallicity.